The present invention relates to a semiconductor-type flow rate detecting apparatus useful for metering the flow rate of intake air of an engine.
Conventional flow meters using a platinum resistance wire such as a Thomas meter and a hot-wire type flow meter are well known. The disadvantages of these flow meters are that the metering element exposed to fluid is made up of a wire and therefore is easily broken by a vibration or a shock.
Another conventional flow meter is of such a construction that a film of resistor is deposited by evaporation or printed on an insulator such as a ceramic substrate. This flow meter has a metering element in film form resistant to vibrations. Since the resistor film is formed by evaporation or printing, however, the metering element cannot be finely processed and therefore is required to be formed in large size, resulting in an increased heat capacity for a deteriorated response characteristic.